In general, a refrigerator is equipment used for keeping stuffs such as foods, beverages and the like in a fresh state for a long term of time, and stores the stuffs in a refrigerated or frozen state according to a type of the stuff.
A refrigerator is driven by an operation of a compressor disposed therein. Cold air supplied into the refrigerator is generated by heat exchange of a refrigerant. The refrigerant is continuously supplied into the refrigerator by a repetitive performance of a cycle of compression-condensation-expansion-evaporation. The refrigerant supplied into the refrigerator is evenly transferred into the refrigerator by convection, such that foods within the refrigerator can be stored at a desired temperature.
Meanwhile, the refrigerator or an air conditioner is equipped with a compressor, and generally uses a brushless direct current (BLDC) compressor or a reciprocating compressor.
Especially, a reciprocating compressor is a compressor in which a piston linearly reciprocates within a cylinder so as to suck, compress and discharge a refrigerant gas. The reciprocating compressors are classified into a recipro type and a linear type according to a method of driving a piston.
The recipro type is employing a method of converting a rotational force of a rotary motor into a linear reciprocating motion by coupling a crankshaft to the rotary motor and a piston to the crankshaft. On the other hand, the linear type is employing a method of reciprocating a piston in response to a linear motion of a linear motor by directly connecting the piston to a mover of the linear motor. The linear type reciprocating compressor exhibits a less frictional loss due to non-use of a crankshaft, which is used to convert the rotating motion into the linear motion. Therefore, the linear type reciprocating compressor has higher compression efficiency than typical compressors.
A refrigerator having a compressor includes a compressor controller for controlling an operation of the compressor and a refrigerator controller for controlling an operation of the refrigerator. Here, the compressor controller detects current and voltage flowing in the compressor and controls stroke or speed using the detected current and voltage. The refrigerator controller controls power of the compressor by outputting a control signal for turning on or off the compressor to the compressor controller according to a refrigerator load, for example, an inner temperature of the refrigerator, and drives the refrigerator accordingly.
In a refrigerator having a linear compressor or a BLDC reciprocating compressor, the compressor receives commercial power and operate via a drive (or driving unit) implemented as a power source such as a TRIAC and the like. The compressor carries out operations, such as power on/off, freezing (cooling) capacity variation, speed control, frequency control, stroke control and the like, according to a command required in the refrigerator. The refrigerator maintains the inner temperature within an appropriate level through the operations of the compressor.
However, in an apparatus and method for controlling a compressor and a refrigerator having the same according to the related art, since the compressor is always driven via a drive implemented as a TRIAC, there is a problem in a loss due to the drive.